1. Field of the Invention
The present invention relates to an oscillating air pressure generator, diaphragm unit, and a high-frequency artificial respiration apparatus using the same.
2. Description of the Related Art
As a conventional example, Japanese Patent Publication No. A2-141774 discloses a high-frequency artificial respiration apparatus for performing oxygen inhale for a patient who cannot inhale and exhale by himself/herself. This high-frequency artificial respiration apparatus includes: a blower capable of simultaneously generating a positive pressure air and a negative pressure air; an oscillating air pressure generator connected to the blower and generating an oscillating air pressure; a diaphragm urged by the oscillating air pressure for transmitting the oscillating air pressure to oxygen for inhale; an oxygen supply source; and an exhale pipe path.
FIG. 53 shows an oscillating air pressure generator 100 mounted on the high-frequency artificial respiration apparatus. This oscillating air generator includes a frame 105 having a positive pressure input port 101 urged by a positive pressure from the blower, a negative pressure input port 102 urged by a negative pressure from the blower; an atmospheric port 103 opening into the atmosphere, and an output port 104 for outputting an oscillating air. Moreover, the oscillating air pressure generator 100 has a switching valve member 106 between a first state and a second state. In the first state, the positive pressure input port 101 is connected to the output port 104, and the negative input port 102 is connected to the atmospheric port 103. In the second state, the positive pressure input port 101 is connected to the atmospheric port 103, and the negative input port 102 is connected to the output port. Switching operation of this switching valve member is continuously urged by a drive unit (not depicted).
The switching valve member 106 is a modified-cylindrical body rotatably arranged in the frame. The drive unit urges this modified-cylindrical body to rotate in a predetermined rotation direction. Moreover, in the frame 105, the positive pressure input port 101 faces one and of the switching valve member 106 and the negative pressure input port 102 faces the other end of the switching valve member. The output port 103 and the atmospheric port 104 are arranged to face the outer circumference of the modified-cylindrical body to sandwich the center shaft of the switching valve member 106.
Furthermore, the switching valve member 106 has a first flow path 107 formed at one end of the switching valve member 106 and a second flow path 108 formed on the other end of the switching valve member 106. These flow paths 107 and 108 are arranged at the opposing positions with respect to the center shaft.
FIG. 54(A) is a cross sectional view about the line Xxe2x80x94X in FIG. 53, and FIG. 54(B) is a cross sectional view about the line Yxe2x80x94Y in FIG. 53. The arrow Z shows the direction of rotation urged by the drive unit. The switching valve member 106 has cut-off portions at the both ends, forming the first and the second flow paths 107 and 108. Each of the cut-off portions are cut off in the range of 180 degrees from the center axis. As shown in FIG. 54(A) and FIG. 54(B), the cut-off portions are symmetric with respect to a diameter of the end surface of the switching valve member 106.
The output port 103 and the atmospheric port 104 have identical width in the rotation direction Z of the switching valve member 106. Thus, the timing of opening and closing of the ports 103 and 104 by the flow paths 107 and 108 are matched each other.
Referring to FIG. 54 through FIG. 57, explanation will be given on the operation of the oscillating air pressure generator 100. In this oscillating air pressure generator 100, according to rotation of the switching valve member 106, the first and the second flow paths 107 and 108 change their states as shown FIG. 54 through FIG. 47. That is, when the positive pressure input port 101 is connected to the output port 103 in the first flow path 107, the negative pressure input port 102 is connected to the atmospheric port 104 in the second flow path 108. Moreover, when the positive pressure input port 101 is connected to the atmospheric port 104 in the first flow path 107, the negative pressure input port 102 is connected to the atmospheric port 104 in the second flow path 108. These connections are performed alternately.
Thus, an oscillating air pressure is generated from the output port 103 at the periodicity defined by the rpm urged by the drive unit, and the atmosphere is taken in and out from the atmospheric port 104 at the same periodicity.
As a second conventional example, there has been developed a high-frequency artificial respiration apparatus for performing oxygen intake to a patient who cannot breath by himself/herself. This high-frequency artificial respiration apparatus includes: a blower for simultaneously generating a positive pressure and a negative pressure; an oscillating air pressure generator connected to blower, for generating an oscillating air pressure; a diaphragm urged to oscillate by the oscillating air pressure and transmitting the oscillating air pressure to oxygen to be supplied; an oxygen source; and pipe paths for supplying oxygen and exhausting exhaled gas.
FIG. 58 shows an oscillating air pressure generator B100 provided in the aforementioned high-frequency artificial respiration apparatus. This oscillating air pressure generator B100 includes a frame 105 having: a positive pressure input port B101 urged by the positive pressure from the blower; a negative input port B102 urged by negative pressure from the blower; an atmospheric port B103 opened to the atmosphere; and an output port B104 for outputting an oscillating air pressure. Moreover, the oscillating air pressure generator B100 includes a switching valve member B106 for selectively switching between a first connection state and a second connection state. In the first connection state, the positive pressure input port B101 is connected to the output port B104, and the negative pressure input port B102 is connected to the atmospheric port B103. In the second connection state, the positive pressure input port B101 is connected to the atmospheric port B103, and the negative pressure input port B102 is connected to the output port B104. The switching operation of this switching valve member 106 is continuously urged by a drive unit (not depicted).
The switching valve member B106 is a valve rotatably mounted in the frame B105. This valve by its rotation can switch between the aforementioned connection states, i.e., the first connection state (FIG. 58 (A)) and the second connection state (FIG. 58 (B)). These connection states are changed from one to the other repeatedly. Thus, the output port B103 outputs an oscillating air pressure at a periodicity identical to the rpm urged by the drive unit while the atmospheric port B104 performs take-in and take-out of the atmosphere at the same periodicity.
Furthermore, in the aforementioned oscillating air pressure generator B100, the output port B104 is connected to the diaphragm and accordingly, not so much noise is caused. However, the atmospheric port B103 is opened to the atmosphere and causes much noise. To cope with this, a silencer 110 is provided in the atmospheric port B103 (see FIG. 59).
The current high-frequency artificial respiration apparatus has a need of improvement in the ventilation amount of the oxygen for the patient and gas from the patient. In order to increase this ventilation amount, it has been confirmed medically that it is advantageous to increase the amplitude pressure of the oscillating air pressure generated by the oscillating air pressure generator.
In the aforementioned first conventional example, the connection of the positive pressure input port 101 with the output port 103 is performed completely simultaneously with the connection of the negative pressure input port 102 with the atmospheric port 104. Accordingly, supply of atmosphere to the blower via the atmospheric port and the negative pressure input port is performed simultaneously with output of the positive pressure air from the output port via the blower and the positive pressure input port. Here, the atmosphere taken in from the atmospheric port takes a certain time until it is finally exhausted from the output port. That is, even if the output port is connected to the blower, the atmosphere cannot reach there so quickly. That is, it is impossible to obtain a sufficient positive pressure gas. Accordingly, in the conventional oscillating air pressure generator cannot effectively convert the positive pressure supplied from the blower, into the oscillating air pressure. And the oscillation amplitude is also too small.
To cope with this, it can be considered to increase the amplitude pressure by using a blower of a greater size. However, this brings about increase of the power consumption and increase of the size and cost of the entire artificial respiration apparatus, which is not desirable.
Moreover, the aforementioned second conventional example has only one atmospheric port B103 through which excess positive pressure air is exhausted and the atmosphere is taken in. Accordingly, only one silencer B110 has been provided.
On the other hand, the noise caused by the excess positive pressure air and the noise caused by take-in of the atmosphere have different frequency characteristics (sound pressure levels for the respective frequency) and the single silencer cannot work for the two different frequency characteristics. That is, it has been impossible to sufficiently reduce the noise.
Moreover, the positive pressure air supplied from the blower has been compressed and normally has a high temperature. As has been mentioned above, when the atmospheric port B103 is commonly used as has been described above, the a portion of positive pressure air remains in the atmospheric port B103 and in the silencer are returned to the bower, which may decrease the service life of the blower.
Moreover, the diaphragm film mounted on the diaphragm unit has the oscillating portion of a uniform thickness. The diaphragm film is preferably oscillated in the vertical direction of the film with a leading head at its center portion. However, when the film thickness is uniform, there is a case that the film surface constitutes a wave instead of reciprocal movement of the entire film. In this state, the oscillating air pressure cannot be transmitted effectively to the oxygen. That is, ventilation between the oxygen and the exhaled gas cannot be performed effectively for the lungs of a patient.
Furthermore, in the aforementioned diaphragm unit, back flow of exhaled gas may be caused. And for hygiene, the entire diaphragm unit is washed each time it is used. The diaphragm unit having the diaphragm film is separated from the blower, so as to wash the entire diaphragm unit including the diaphragm film. Furthermore, care should also be taken for the blower, i.e., the connection portion with the diaphragm unit, so that no dusts come into the blower. Thus, the aforementioned diaphragm unit requires a troublesome work.
Moreover, the conventional high-frequency artificial respiration apparatus generates an oscillating air pressure by alternately selecting the positive and the negative pressures from the blower. In this case, during the output of the positive pressure, the negative pressure output is opened to the atmosphere to take in the atmosphere. That is, these two operations are simultaneously performed. Accordingly, the atmosphere taken in needs time to reach the output as a positive pressure. That is, it is impossible to obtain a sufficiently high positive pressure, disabling to obtain effective ventilation between oxygen and exhaled gas for lungs of a patient.
Furthermore, in the oscillating air pressure generator, during a negative pressure output, the positive pressure output side is open to the atmosphere. And this oscillating air pressure generator has only one atmospheric port for exhausting the positive output and for taking in the atmosphere. Accordingly, a positive pressure air at an increased temperature by compression is taken in to be supplied to the blower, which significantly decreases the service life of the blower.
Moreover, it is desired to reduce the aforementioned two noises, i.e., the noise caused when exhausting the positive pressure by the atmospheric port of the oscillating air pressure generator and the noise caused by take-in of the atmosphere.
Moreover, it has been desired to reduce the noise caused when the atmospheric air is exhausted and the noise caused when the atmospheric air is taken in.
It is therefore an object of the present invention to provide an oscillating air pressure generator and a diaphragm unit capable of reducing the power consumption and costs as well as reducing their size and to provide a high-frequency artificial respiration apparatus using such oscillating air pressure generator and diaphragm unit.
The present invention provides an oscillating air pressure generator connected to an air pressure supplier for simultaneously generating a positive pressure and a negative pressure, said oscillating air pressure generator alternately selecting the positive pressure or the negative pressure for output for generating an oscillating air pressure and comprising:
a frame including a positive pressure input port urged by the positive pressure from the air pressure supplier, a negative pressure input port urged by the negative pressure from the air pressure supplier, an atmospheric port open to the atmosphere, and an output port for outputting the oscillating air pressure;
a switching member for selectively switching between a connection state where the positive pressure input port is connected to the output port while the negative pressure input port is connected to the atmospheric port and a connection state where the positive pressure input port is connected to the atmospheric port while the negative pressure input port is connected to the output port; and
a drive unit for continuously driving the switching operation of the switching member.
Here, the connection between the positive pressure input port and the output port and the connection between the negative pressure input port and the atmospheric port are performed by the switching member in such a manner that the connection between the negative pressure input port and the atmospheric port slightly precedes the connection between the positive pressure input port and the output port.
In this configuration, the positive pressure input port and the negative pressure input port are connected to the air pressure supplier. The air pressure supplier take in the atmospheric air through its negative pressure generation section and exhausts the atmospheric air through its positive pressure output section. Accordingly, when the atmospheric air is taken in effectively by the negative pressure, the positive pressure can be effectively output.
In the oscillating air pressure generator, when the switching member connects the positive pressure input port with the output port, and the negative pressure input port with the atmospheric port, the atmospheric air is taken in from the atmospheric port and supplied via the negative input port to the air pressure supplier. Moreover, the atmospheric air take in is output as a positive pressure from the output port via the positive pressure input port.
When the switching member has made a connection between the positive pressure input port and the atmospheric port and a connection between the negative pressure input port and the output port, a gas is sucked at the output port. Furthermore, the gas taken in is sucked via the negative input port by the air pressure supplier and exhausted via the positive pressure input port and the atmospheric port.
The switching member continuously repeats the aforementioned connection states, and at the output port, suction and exhaust are successively performed, generating an oscillating air pressure.
Here, in the aforementioned invention, when the positive pressure input port is connected to the output port and the negative port is connected to the atmospheric port by the switching member, the connection between the negative pressure input port slightly precedes the connection between the positive pressure input port and the output port, so that the atmospheric air is supplied to the air pressure earlier and the positive pressure gas supplied from the air pressure supplier is output immediately after the output port and the positive pressure input port is connected.
Here, the switching member may be constituted by a cylindrical body rotatably mounted on the frame and driven to rotate in a predetermined direction by the drive unit, wherein
the positive pressure port faces one end of the switching member, the negative pressure port faces the other end of the switching member, and the output port and the atmospheric port are arranged on the outer circumference so as to sandwich the center shaft;
a first flow path is arranged from one end of the switching member to its outer circumference, and a second flow path is arranged from the other end of the switching member to its outer circumference;
the second flow path or the atmospheric port is arranged in such a manner that the second flow path has already made connection with the atmospheric port when the first flow path is at a position to start connection with the output path.
Moreover, the switching member may be a body of revolution mounted rotatably on the frame and the drive unit urges the switching member to rotate in a predetermined direction; wherein
in the switching member there are formed a third flow path for communication the positive pressure input port with the output port, a fourth flow path for communicating the positive pressure input port with the atmospheric port, a fifth flow path for communicating the negative pressure input port with the output port, and a sixth flow path for communicating the negative input port with the atmospheric port;
when the switching member is at a first rotation angle, the fourth flow path and the fifth flow path are established;
when the switching member is at a second rotation angle, the sixth flow path is established, and
when the switching member is at a third rotation angle, the third flow path is established,
wherein a difference between the first rotation angle and the second rotation angle is slightly smaller than the difference between the first rotation angle and the third rotation angle.
Moreover, the switching member may be constituted by a rotary disc rotatably mounted on the frame and is driven to rotate in a predetermined direction by the drive unit,
one side of the rotary disc is divided into an inner area and an outer area by a cylinder having a smaller diameter than the rotary disc, so that the output port area is arranged in the inner area and the atmospheric port is arranged in the outer area or vice versa,
the other side of the rotary disc is divided into two semicircles for serving as the positive pressure input port and the negative pressure input port,
two lines passing through the center of the rotary disc defines four areas, from which two sector areas having an angle no greater than 90 degrees are further divided into inner areas and outer areas, and a through hole is provided in one of the inner areas and in an outer area of the other sector, and
the through hole facing the atmospheric port has a continuous additional opening at the upstream side of the rotation.
Furthermore, the switching member may be constituted by a rotary disc rotatably mounted on the frame and is driven to rotate in a predetermined direction by the drive unit,
one side of the rotary disc is divided into an inner area and an outer area by a cylinder having a smaller diameter than the rotary disc, so that the positive air pressure input port is arranged in the inner area and the the negative pressure input port is arranged in the outer area or vice versa,
the other side of the rotary disc is divided into two semicircles for serving as the output port and the atmospheric port,
two lines passing through the center of the rotary disc defines four areas, from which two sector areas having an angle no greater than 90 degrees are further divided into inner areas and outer areas, and a through hole is provided in one of the inner areas and in an outer area of the other sector, and
the through hole facing the negative pressure input port has a continuous additional opening at the upstream side of the rotation.
Furthermore, two of the atmospheric ports may be provided, one for connection with the positive pressure input port and the other for connection with the negative pressure input port.
Moreover, the present invention provides an oscillating air pressure generator for use in a high-frequency artificial respiration apparatus, the oscillating air pressure generator being connected to an air pressure supplier for simultaneously generating a positive pressure and a negative pressure, and alternately selecting the positive pressure or the negative pressure for output for generating an oscillating air pressure and comprising: a take-in opening for introducing the atmospheric air and an exhaust opening for exhausting an excess positive pressure air,
wherein the take-in opening has an inhale silencer based on the frequency characteristic of a noise generated at the take-in opening and the exhaust opening has an exhaust silencer based on the frequency characteristic of a noise generated at the exhaust opening.
That is, the oscillating air pressure generator of the high-frequency artificial respiration apparatus has a take-in opening for taking in the atmospheric air and an exhaust opening for exhausting an excessive positive pressure air and the former has an inhale silencer and the latter has an exhaust silencer. This can separate the position for exhausting an excessive positive pressure air from the position for taking in the atmospheric air. Thus, the excessive positive air will not be introduced into the oscillating air pressure generator of the high-frequency artificial respiration apparatus.
Furthermore, since the exhaust silencer and the inhale silencer are provided separately, it is possible to sufficiently reduce the noise having different frequency characteristics at the exhaust opening and at the take-in opening.
Furthermore, the inhale silencer may include: a sound absorbing path forming a flow path for the atmospheric air; and a resonance chamber having a partition to form a closed space adjacent to the atmospheric air flow path, and a single communication hole provided in this partition for communication between the closed space and the atmospheric air flow path.
Moreover, the inhale silencer may include an air filter having a net filter portion of a cylindrical shape for preventing dusts and a cover portion of a cylindrical shape.
Furthermore, the inhale silencer may have a sound absorbing path having a sufficient length in comparison to its width. In this case, the sound absorbing path is preferably formed in a spiral shape.
Moreover, the exhaust silencer may include: a sound absorbing path surrounded by a sound absorbing material for passing the positive pressure air; and an expansion chamber having a partition to define a closed space and an entrance and an exit formed in this partition for the positive pressure air.
Moreover, the exhaust silencer may include: a partition to form a closed space in the positive pressure air path; and a resonance chamber having a single communication opening provided in the partition for communication between the closed space and the positive pressure air path.
The aforementioned spiral flow path member can reduce the sound pressure level of the entire frequency band.
The aforementioned expansion chamber has been found experimentally to reduce the sound pressure level of almost the entire frequency band.
The aforementioned resonance chamber includes a partition to form a closed space adjacent to the gas flow passage and a single communication hole provided in the partition communicating with the gas flow passage. In the chamber serving as the gas flow passage adjacent to the resonance chamber via the communication hole, a low-frequency noise around 100 Hz is reduced. This has been confirmed experimentally (see FIG. 37(B)).
The aforementioned sound absorbing path is made from a sound absorbing material. When the gas passes through this sound absorbing path, the frequency of 500 Hz or higher can be reduced. This has been experimentally confirmed (see FIG. 37(C)).
These are used in combination according to the noise frequency characteristic, so that the silencer can effectively lower the noise.
Moreover, the high-frequency artificial respiration apparatus according to the present invention comprises: an inhale gas supply unit for supplying oxygen to a patient; an air pressure supplier for simultaneously generating positive pressure air and a negative pressure air; an oscillating air pressure generator for alternately selecting the positive or the negative pressure for output of an oscillating air pressure; a diaphragm unit urged by the oscillating air to apply the oscillating air pressure to the oxygen to be supplied to the patient from the inhale gas supply unit.
The diaphragm unit includes: a hollow container having an input opening for taking in the oscillating air pressure and an output opening for outputting the oscillating air pressure to the oxygen; and an elastic diaphragm film to divide the container into the side of the input opening and the side of the output opening, wherein the diaphragm has a thicker portion at its center portion than the peripheral portion.
Since the diaphragm film has a thicker portion at its center portion, when the diaphragm film, when subjected to the oscillating air pressure, reciprocally moves in a vertical direction to the diaphragm film and accordingly the entire diaphragm film simultaneously moves reciprocally. Thus, the oscillating air pressure is effectively transmitted to the oxygen.
The oscillating air pressure generator includes a frame, a switching member, and a drive unit. The frame includes a positive pressure input port subjected to the positive pressure from the air pressure supplier, a negative pressure input port subjected to the negative pressure from the air pressure supplier, an atmospheric port open to the atmospheric air, and an output port for outputting an oscillating air pressure.
Furthermore, the switching member selectively switches between a connection state where the positive pressure input port is connected to the output port while the negative pressure input port is connected to the atmospheric port and a connection state where the positive pressure input port is connected to the atmospheric port while the negative pressure input port is connected to the output port.
Moreover, the drive unit continuously drives switching operation of the switching member.
Furthermore, when the positive pressure input port is connected to the output port while the negative pressure input port is connected to the atmospheric port by the switching member, the connection between the negative pressure input port and the atmospheric port is made slightly earlier than the connection between the positive pressure input port and the output port.
Thus, the atmospheric air is supplied to the air pressure supplier in advance, and the positive pressure gas supplied from the air pressure supplier is output immediately after the output port is connected to the positive pressure input port. Accordingly, it is possible to maintain a high positive pressure output.
The diaphragm unit has a container which can be divided into a first diaphragm section having an input opening and a second diaphragm section having an output opening. Each of the first and the second diaphragm sections has a match plane which is matched with each other when the first and the second diaphragm sections are connected.
The diaphragm unit also has a holding mechanism for maintaining the connected state and two diaphragm films, at least one of which has a thicker portion at its center portion.
After a use of the high-frequency artificial respiration apparatus, the holding mechanism is released to separate the diaphragm container into the first diaphragm section and the second diaphragm section. Here one of the diaphragm films attached to the first diaphragm section is left as it is, and only the diaphragm of the second diaphragm section is replaced with a new one or washed and sterilized. And only the second diaphragm section is washed.
After the washing, the diaphragm film is set on the second diaphragm section and connected to the first diaphragm section with their match planes matched. The first and the second diaphragm sections are linked and fixed by the holding mechanism.
Since two diaphragm films are used, and the diaphragm film of the first diaphragm section is not in contact with the inhale gas, it does not require washing or sterilization. When the second diaphragm section is disconnected, the diaphragm of the first diaphragm section can remain as it is. Accordingly there is no danger of intrusion of dusts or germs into the first diaphragm section.
Accordingly, by washing and sterilizing only the second diaphragm section and its diaphragm film, it is possible to maintain a sufficiently clean state. The first diaphragm section need not be disconnected from the oscillating air pressure generator.
The switching member is constituted by a cylindrical body rotatably mounted on the frame and the drive unit urges the cylindrical body to rotate in a predetermined direction.
Furthermore, the positive pressure input port faces one end of the switching member and the negative pressure input port faces the other end of the switching member.
The output port and the atmospheric port are arranged on the outer circumference of the switching member so as to sandwich the rotary shaft of the switching member.
A first flow path is arranged at a location from one end to the outer circumference of the switching member, and a second flow path is arranged at a location from the other end to the outer circumference of the switching member. The second flow path or the atmospheric port is arranged in the following manner. When the first flow path is to be connected with the output port, the second flow path has been already connected with the atmospheric port and at the upstream position by 20 to 50 degrees.
With the aforementioned configuration, the atmospheric air is taken in earlier by the 20 to 50 degrees prior to the output of the positive air pressure.
Moreover, the atmospheric port of the oscillating air pressure generator consists of a take-in opening for taking in the atmospheric air and an exhaust opening for exhausting an excessive positive pressure air. This prevents introduction of positive pressure air.
Moreover, an inhale silencer is provided at the take-in opening for the frequency characteristic of the noise caused at the take-in opening, and an exhaust silencer is provided at the exhaust opening for the frequency characteristic of the noise caused at the exhaust opening.
Thus, the inhale silencer and the exhaust silencer are employed for reducing the noises of different frequency characteristics and accordingly, the two different noises can be effectively reduced.
Furthermore, the diaphragm unit according to the present invention for transmitting the oscillating air pressure output from the oscillating air pressure generator includes: a hollow container having an input opening for taking in the oscillating air pressure and an output opening for outputting the oscillating air pressure to the oxygen.
The hollow container can be divided into a first diaphragm section having the input opening and a second diaphragm section having the output opening. The first and the second diaphragm sections have match planes facing to each other when the first and the second diaphragm sections are connected. The diaphragm unit includes a holding mechanism for maintaining the aforementioned connected state and two diaphragm films. One of the diaphragm films is attached to the first diaphragm section and the other is attached to the second diaphragm section, so that the diaphragm films are adjacent to each other when the first and the second diaphragm sections are connected.
Here, the diaphragm film of the first diaphragm section may be detachably attached to the match plane. Similarly, the diaphragm film of the second diaphragm section may also be detachably attached to the match plane of the second diaphragm section.
With this configuration, when the first diaphragm section is separated from the second diaphragm section, the diaphragm films are respectively attached to the match planes. Accordingly, there is no danger of unnecessary removal of the diaphragm films. The diaphragm of the second diaphragm section is removed for washing and sterilization.
Moreover, each of the diaphragm films has a flange portion at its periphery and each of the match planes has an insert groove for inserting the diaphragm film. Furthermore, at least one of the diaphragm films may have a tab.
In this case, each of the diaphragm films is mounted on the corresponding match plane by inserting the flange portion into the insert groove, and is separated from the match plane by pulling out the flange portion. When the tab is present, it is possible to pull the tab so as to pull out the flange portion from the insert groove.
Furthermore, one of the diaphragm films may have a protrusion continuously arranged around the periphery to serve as a check valve.
In this case, when the diaphragm films are held adjacent to each other, the end of the protrusion is in contact with the other diaphragm film. Here, the end of the protrusion is slanting outwardly, and the air present in a clearance between the diaphragm films can easily be discharged by further slanting the protrusion. On the contrary, intrusion of the atmospheric air into the clearance is prevented by the protrusion. Thus, the protrusion functions as a one-way valve.
Furthermore, the holding mechanism may include: a first holding frame for holding the first diaphragm section; a second holding frame for holding the second diaphragm section; a linkage body for rotatably linking the holding frames; and a connection urging mechanism for urging the first diaphragm section and the second diaphragm section to each other in a direction for bringing the match planes to be in contact with each other.
In this case, the linkage body is preferably arranged on one of the holding frames and includes: a rotary shaft arranged in the vicinity of one of the holding frames and capable of moving toward the holding frame; and an engagement member rotatably engaged with the rotary shaft. The connection urging mechanism includes: a claw member arranged on one of the holding frames so as to be slidable along the matching plate of the diaphragm section held by the holding frame; an engagement member arranged on the other holding frame, where the claw member is to be engaged; and a lever unit to move the claw member by a user. The claw member has a slanting portion to guide the claw into the engagement member.
In the aforementioned holding mechanism, the connection urging mechanism is released and one of the support frames is rotated with respect to the other support frame so as to separate the first diaphragm section and the second diaphragm section.
Explanation will be given on the engagement by the connection urging mechanism and release of the engagement. For engagement, the support frames holding the first diaphragm section and the second diaphragm section are brought into close positions where the claw member can reach the engagement member. The claw member is moved by the lever unit, so that the engagement member is brought into abutment with the slanting portion of the claw member, which slides along the slanting portion. Thus, the support frame having the engagement member is pulled toward the other support frame. Here, a rotary shaft linking the support frames can move closer to the support frame having the rotary shaft. Thus, the diaphragm films are held between the match planes.
When releasing the engagement, the claw member is moved to slide in the opposite direction, so that the engagement member is moved apart from the support frame having the claw member and apart from the end of the claw member. Accordingly, each of the support frames is in a rotatable state and the support frames are separated from each other.
The present invention has the aforementioned function to attain the aforementioned object.